Self-locking box



Sept. 27, 1966 W. H. MCKEc m 3,275,219

SELF-LOCKING BOX Original Filed Aug. 5, 1964 United States Patent 3,275,219 SELF-LOCKING BOX William H. McKechnie, Northboro, Mass, assignor to Dennison Manufacturing Company, Framingham, Mass, a corporation of Nevada Original application Aug. 5, 1964, Ser. No. 387,606. Divided and this application June 14, 1965, Ser. No.

4 Claims. (Cl. 22945) This is a division of Ser. No. 387,606, filed August 5, 1964- and now abandoned.

This invention relates to boxes having inner and outer parts which telescope together with the edge of the inner part inside the outer part and the edge of the outer part outside the inner part. Usually the inner part constitutes the bottom of the box and the outer part constitutes the cover. The invention is p'atricularly applicable to boxes made of cardboard covered with paper, cloth or other sheet material.

Objects of the invention are to provide a box in which the cover locks automatically when telescoped onto the "bottom, which can be unlocked by pressing on a predetermined portion of the box, which is simple and economical to produce and which is reliable in use.

According to this invention the box comprises inner and outer cup-shaped parts which telescope together with the edge of the inner part inside the outer part and the edge of the outer part outside the inner part, an internal shoulder on one side of the outer part facing away from the edge of the outer part, a flap on the corresponding side of the inner part having its free end directed away from the edge of the inner part to engage behind the aforesaid shoulder when the parts are telescoped together, the outer part having a depressible portion opposite the aforesaid flap so that the flap may be disengaged from the shoulder by pressing inwardly on the aforesaid portion to unlock the box, the inner part comprising a layer of material covered with sheet material which bends easily, said sheet material extending across the junction between said flap and inner part and being secured to both the flap and inner part on opposite sides of the junction, said layer having a cut along said junction to facilitate folding the flap outwardly with said sheet material serving as a hinge. Preferably the depressible portion is formed by a cut in the layer which may form an opening in the layer. The aforesaid fiap may comprise an integral extension of the corresponding side of the inner part of the box or it may be cut in said corresponding side of the inner part of the box, and in either case it is hinged to the inner part of the box.

In a more specific aspect the invention involves a box comprising a bottom and a cut-shaped cover which telescopes over the bottom with a shoulder on the inner face of one side of the cover facing upwardly and a flap on the outer face of the corresponding side of the bottom having its free end directed downwardly to engage behind the aforesaid shoulder on the sover when the parts are telescoped together, the cover having a depressible portion opposite the flap so that the flap may be disengaged from the shoulder by pressing inwardly on the tab to unlock the box. Preferably the aforesaid shoulder comprises an integral extension of the aforesaid side of the bottom folded outwardly about the upper edge of the aforesaid side of the bottom.

For the purpose of illustration typical embodiments of the invention are shown in the accompanying drawing in which FIG. 1 is a side elevation with the top and bottom separated;

FIG. 2 is a similar view in longitudinal section;

FIG. 3 is a transverse section with the flap flolded outwardly;

FIG. 4 is a similar view with the parts telescoped together; and

FIGS. 5, 6, 7 and 8 are views like FIGS. 1, 2, 3 and 4 showing a modification.

In the embodiment shown in FIGS. 1 to 4 B is the box and C is the cover. When the parts are telescoped together the edge 11 of the box is inside the cover and the edge 12 of the cover is outside the box. Bot-h the box and cover are formed of an inner layer 14 of cardboard and an outer cover 15 of paper, cloth or other sheet material.

According to the present invention the cover C is provided at each side with a shoulder 16 directed away from the edge 12, each shoulder being provided by cutting an opening 17 in the side of the cover. Likewise the box B is provided at each side with an integral extension 18 which is folded outwardly in the .form of a flap. The flap 18 is preferably formed by cutting the cardboard along the dotted line 19 but not through the cover sheet 15. While a flap 18 may be formed at each side of the box, it may be sufficient to have a flap at only one side so that the other side may be swung away from the box until the edges 11 and 12 separate whereupon the cover may be shifted endwise to disengage the cover at the flap side. Indeed the cover may be hinged to the box at the side opposite the flap so it merely swings open about the hinge line. The covering sheet 15 may be perforated at 13 opposite the opening 17 to facilitate the operation of disengaging the flap 18 from the shoulder 16.

The modification shown in FIGS. 5 to 8 is similar to the first embodiment and corresponding parts are correspondingly designated, this modification comprising a box B having an upper edge 21, a cover C having a lower edge 22 and a shoulder 26 directed away from its lower edge, and a flap 28 on the box to engage behind the shoulder 26. Both the box and cover are formed of cardboard 24 and an outer cover 25 of sheet material. As in FIGS. 1 to 4 the shoulder 26 is formed by cutting out a portion 27 of the inner layer 24 of the upper part C. However it differs from the embodiment shown in FIGS. 1 to 4 in that the flap 28 is cut out of the side of the box B instead of projecting above the upper edge 21 of the box, the flap being hinged to the box by means of the cover sheet 25 as in the previous embodiment.

The aforesaid flap is cut either before or after the sheet of covering material is applied but if cut before it is cut from the inside and not quite all the way through the cardboard so as to remain in place while the sheet of covering material is applied. In either case the hinge is formed by the covering material.

From the foregoing it will be understood that before the cover is telescoped over the box the flaps 18 and 2 8 are folded down from the positions shown in FIGS. 1, 2, 5 and 6 to the positions the shown in FIGS. 3, 4, 7 and 8 so as to engage behind the shoulder of the cover. To unlock the box inward pressure is exerted on the outside of the cover opposite the flaps to disengage the flaps from the shoulders on the cover. If the boxes are to be unlocked indications such as 13 and 23 may be provided in the covering material to indicate where to :press in order to disengage the flap.

It should be understood that the present disclosure is for the purpose of illustration only and that this invention includes all modifications and equivalents which fall within the scope of the appended claims.

I claim:

1. A self-locking box comprising inner and outer cupshaped parts which telescope together with the edge of the inner part inside the outer part and the edge of the outer part outside the inner part, an internal shoulder on one side of the outer part facing away from said edge of the outer part, and a flap on the corresponding side of the inner part having its free end directed away from said edge of the inner part to engage behind said shoulder when the parts are telescoped together, the outer part having a depressible portion opposite said flaps so that the flap may be disengaged from said shoulder by pressing inwardly on the said portion to unlock the box, the inner part comprising a layer of material covered with sheet material which bends easily, said sheet material extending across the junction between said flap and inner part and being secured to both the flap and inner part on opposite sides of the junction, said layer having a cut along said junction .to facilitate folding the flap outward- 1y with said sheet material serving as a hinge.

2. A self-locking box according to claim 1 wherein said flap comprises an extension projection beyond the plane of the edge of the inner part.

3. A self-locking box according to claim 1 wherein said 4 flap is cut in the side of the inner part With its free end in the plane of the edge of the inner part.

4. A self-locking box according to claim 1 wherein said outer part also comprises a layer of material having a covering which can be deformed easily, said depressi'ble portion having an indication on said covering to indicate the location of said flap.

References Cited by the Examiner UNITED STATES PATENTS 1,130,271 3/1915 Hammond 229-45 2,412,402 12/1946 Huye 22.9-45 2,577,248 12/1951 James 22945 2,745,589 5/1956 Daly et a1 22945 THERON E. CONDON, Primary Examiner.

I. R. GARRETT, Assistant Examiner. 

1. A SELF-LOCKING BOX COMPRISING INNER AND OUTER CUPSHAPED PARTS WHICH TELESCOPE TOGETHER WITH THE EDGE OF THE INNER PART INSIDE THE OUTER PART AND THE EDGE OF THE OUTER PART OUTSIDE THE INNER PART, AN INTERNAL SHOULDER ON ONE SIDE OF THE OUTER PART FACING AWAY FROM SAID EDGE OF THE OUTER PART, AND A FLAP ON THE CORRESPONDING SIDE OF THE INNER PART HAVING ITS FREE END DIRECTED AWAY FROM SAID EDGE OF THE INNER PART TO ENGAGE BEHIND SAID SHOULDER WHEN THE PARTS ARE TELESCOPED TOGETHER, THE OUTER PART HAVING A DEPRESSIBLE PORTION OPPOSITE SAID FLAPS SO THAT THE FLAP MAY BE DISENGAGED FROM SAID SHOULDER BY PRESSING INWARDLY ON THE SAID PORTION TO UNLOCK THE BOX, THE INNER PART COMPRISING A LAYER OF MATERIAL COVERED WITH SHEET MATERIAL WHICH BENDS EASILY, SAID SHEET MATERIAL EX- 